Oxalate oxidase (OxOx), a well known enzyme catalyzes the cleavage of oxalate to carbon dioxide with reduction of dioxygen to hydrogen peroxide, however its catalytic process is not well understood. To define the substrate binding site, interaction of Fe3+ ions with OxOx was systemically investigated using biochemical method, circular dichrosim spectroscopy, microscale thermophoresis, and computer modeling. We demonstrated that Fe3+ is a non-competitive inhibitor with a milder binding affinity to OxOx, and the secondary structure of the OxOx was slightly altered upon its binding. On the basis of the structural properties of the OxOx and its interaction with Fe3+ ions, two residue clusters of OxOx were assigned as potential Fe3+ binding sites, the mechanism of the inhibition of Fe3+ was delineated. Importantly, the residues that interact with Fe3+ ions are involved in the substrate orienting based on computer docking. Consequently, the interaction of OxOx with Fe3+ highlights insight into substrate binding site in OxOx.
Bibliographical noteFunding Information:
This work was supported by the State key laboratory of bioreactor engineering (No. 2060204), NSFC of China (No. 20671034), and 111 Project (B07023).
© 2015 Springer Science+Business Media New York.
- Computer modeling
- Fe ion
- Oxalate oxidase
- Substrate binding site